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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
2
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pubmed:dateCreated |
1993-9-10
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pubmed:abstractText |
The function of the ectoenzyme NAD glycohydrolase (NADase) in ADP-ribose uptake from extracellular NAD was studied in human erythrocytes that express relatively high NADase activity (adult erythrocytes) and erythrocytes expressing very low activity (newborn erythrocytes). The rates of ADP-ribose uptake from NAD in human erythrocytes were correlated with their NADase activities. In contrast, there was no significant difference in the rates of ADP-ribose uptake among these cells when incubated with ADP-ribose. These results indicate that ecto-NADase may have a role as supplier of ADP-ribose for its uptake into the cells and that the cleavage of NAD by NADase is necessary for the ADP-ribose uptake by human erythrocytes. From ADP-ribose uptake studies at 37 degrees C a Km of 0.7 +/- 0.05 microM and a Vmax of 2.04 +/- 0.1 pmol/min per microliter cell water was found for the uptake of [3H]ADP-ribose. The thiol-reactive reagents p-chloromercuribenzene sulfonic acid and N-ethylmaleimide inhibited the uptake ADP-ribose with IC50 values of 50 +/- 4 and 750 +/- 25 mM, respectively. Since efflux of [3H]ADP-ribose was negligible, the ADP-ribose transport system appears to be unidirectional. The unidirectionality was supported by the evidence that transported ADP-ribose was rapidly degraded to AMP which is impermeable to the membrane.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Aug
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pubmed:issn |
0006-3002
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
18
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pubmed:volume |
1178
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
121-6
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:8394137-Adenosine Diphosphate Ribose,
pubmed-meshheading:8394137-Adult,
pubmed-meshheading:8394137-Aging,
pubmed-meshheading:8394137-Biological Transport,
pubmed-meshheading:8394137-Erythrocytes,
pubmed-meshheading:8394137-Humans,
pubmed-meshheading:8394137-Infant, Newborn,
pubmed-meshheading:8394137-NAD,
pubmed-meshheading:8394137-NAD+ Nucleosidase
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pubmed:year |
1993
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pubmed:articleTitle |
Function of NAD glycohydrolase in ADP-ribose uptake from NAD by human erythrocytes.
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pubmed:affiliation |
Department of Biochemistry, Chonbuk National University Medical School, Chonju, South Korea.
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pubmed:publicationType |
Journal Article,
In Vitro
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